Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 b2ed59169f13ce72…

MALICIOUS

Office (OLE) / .XLSX

1.13 MB
MD5: 71dcb617ee49141e7baec40a4f3f52d9 SHA-1: ebff9f2e75b9ec12af11170b7bfd322852672f83 SHA-256: b2ed59169f13ce72fd84dd49f35a9212a824dd9a094fcdbc7db2bdaec9ecd555
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Phishing: Spearphishing Attachment T1027 Obfuscated Files or Information

The sample is an encrypted OOXML file that uses the 'VelvetSweatshop' default password to evade detection. It contains an embedded OLE object with the Equation Editor CLSID and a malformed Ole10Native stream, which is characteristic of exploits targeting CVE-2017-11882. No scripts were extracted from this sample, but the structural anomalies in the OLE object strongly indicate an exploit-based delivery mechanism.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Default-encrypted OOXML embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • Default-encrypted OOXML exploit carrier layout high OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE
    Default-password encrypted OOXML package contains embedded OLE object parts and additional activation/decoy parts. This layout is common in malicious Excel exploit delivery and requires inspecting the decrypted package.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • Office OOXML encrypted with default VelvetSweatshop password medium OFFICE_DEFAULT_PASSWORD_ENCRYPTED_OOXML
    OLE EncryptedPackage decrypts with Excel's built-in VelvetSweatshop password. Office opens this transparently, and malware uses it to hide OOXML exploit parts from scanners that only inspect the outer OLE container.